Latent tracks of swift Bi ions in Si₃N₄

Abstract

Parameters such as track diameter and microstruture of latent tracks in polycrystalline Si 3 N 4 induced by 710 MeV Bi ions were studied using TEM and XRD techniques, and MD simulation. Experimental results are considered in terms of the framework of a 'core-shell' inelastic thermal spike (i-TS) model. The average track radius determined by means of electron microscopy coincides with that deduced from computer modelling and is similar to the track core size predicted by the i-TS model using a boiling criterion. Indirect (XRD) techniques give a larger average latent track radius which is consistent with the integral nature of the signal collected from the probed volume of irradiated material.

Study of the Influence of the Irradiation Flux Density on the Formation of a Defect Structure in AlN in the Case of the Effect of Overlapping of the Heavy Ion Motion Trajectories in the Near-Surface Layer

“…In this case, the absence of the appearance of new diffraction reflections or the stratification of the observed reflections indicates the absence of processes of phase or polymorphic transformations in the composition of ceramics because of irradiation. It should be noted that in the case of AlN ceramics having a hexagonal type of crystal lattice, according to several works [11,31,32], irradiation with heavy ions does not cause the formation of structurally changed regions in the form of discontinuous or extended latent tracks, which are observed in silicon nitride. Several authors [33][34][35] attribute such differences in nitride ceramics to a higher binding energy in aluminum nitride, which prevents the formation of latent tracks.…”

“…The appearance of such effects may be due to both anisotropic changes in structural properties and more pronounced texturing effects. It should also be noted that a large difference between electronic and nuclear losses can lead to the formation of amorphous tracks or inclusions in the structure of ceramics, for silicon nitride (Si 3 N 4 ), which was reported in [32][33][34]. However, for aluminum nitride (AlN) ceramics, such latent tracks were not observed, and several authors [35,45] recrystallization or reorientation of grains as a result of the accumulation of deformation distortions and stresses.…”

Study of Changes in Optical and Heat-Conducting Properties of AlN Ceramics under Irradiation with Kr15+ and Xe22+ Heavy Ions

“…The samples were irradiated in a vacuum chamber on a water-cooled target in order to avoid local overheating of the sample under irradiation. According to the literature [10,32], in the case of irradiation with heavy ions with an energy of more than 100 MeV, when a heavy ion passes through the target material, the radius of the defect region, which in some cases is called a latent track, is estimated to be from 3 to 10-20 nm. This region is a defect structure arising from the interaction of an incident ion with the electronic and nuclear subsystem of the target.…”

“…This region is a defect structure arising from the interaction of an incident ion with the electronic and nuclear subsystem of the target. An increase in the irradiation fluence above 10 13 ion/cm 2 leads to overlapping of these regions [10,32].…”

“…From a fundamental point of view, interest in these materials is due to the possibility of obtaining new knowledge in the field of studying the mechanisms of defect formation, tread formation and radiation resistance of materials [7][8][9]. At the moment, among all nitride ceramics, latent tracks from heavy ions were found in Si 3 N 4 [10,11], while for AlN, the formation of latent tracks was not found, which the authors of [12] determined with a high threshold bias energy for AlN (>34 keV/nm) required to form tracks. In this regard, high resistance to radiation damage, as well as good insulating and heat-conducting properties, make ceramics based on AlN one of the most promising materials in the field of nuclear energy, structural materials for reactor building, dosimetry, etc.…”